Scholarship, Studenthttp://hdl.handle.net/10829/23
Fri, 23 Nov 2018 18:11:09 GMT2018-11-23T18:11:09ZInducing Diffuse Phase Transitions in Barium Titanate Using Ga3+-Ta5+ Dipole Pair Substituentshttp://hdl.handle.net/10829/8237
Inducing Diffuse Phase Transitions in Barium Titanate Using Ga3+-Ta5+ Dipole Pair Substituents
Veerapandiyan, Vignaswaran
Ba{[Gax,Tax]Ti(1-2x)}O3 with x equal to 0, 0.0025, 0.005, 0.01, 0.025 and 0.05 have been prepared by conventional solid-state reaction and sintered to greater than 95% density. Structural and dielectric characterization have been performed to investigate the effect of dipole-pair concentration on the properties. Dielectrically, the Ba{[Gax,Tax]Ti(1-2x)}O3 phase transition evolves from a classic ferroelectric to a diffuse phase transition (DPTs) as x increases. Ba{[Gax,Tax]Ti(1-2x)}O3 for 𝑥≥0.01 possesses diffuseness parameters comparable to Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), yet it lacks the frequency and temperature dependence of Tm necessary to be a strictly defined relaxor ferroelectric. Additionally, Ba{[Ga0.05, Ta0.05]Ti0.9}O3 possesses a relative permittivity, εr, of 700±16% and dissipation factor less than 0.05 at 10 kHz within the temperature range [-75°C, 120°C]. In comparison to BaTiO3, Ba{[Gax,Tax]Ti(1-2x)}O3 possesses enhanced electrical resistivity and greater time constant at and above room temperature. Through varying the concentration of dipole-like substitutions, material evolution of properties could be systematically investigated and material properties like resistivity, RC time constant, breakdown strength, maximum εr, temperature sensitivity of εr, dissipation factor, etc. can be individually optimized or any combination(s) of material properties can be optimized to achieve desired device or system performance. The relaxation of εr is found to increase linearly with the dipole concentration. In-situ XRD, including Rietveld refinement, have been performed to determine the lattice parameter, coefficient of thermal expansion and phase transition temperature of each composition within the temperature range [RT, 1000°C]. The unusual properties of Ba{[Gax,Tax]Ti(1-2x)}O3 are discussed in context with available models describing donor and acceptor dopants spatially separated in the parent matrix that inter-relate lattice parameter, Curie temperature, and other material properties.
Dissertation completed in partial fulfillment of the requirements for the degree of Masters in Science in Ceramic Engineering at the Inamori School of Engineering, New York State College of Ceramics at Alfred University
Thu, 01 Jun 2017 00:00:00 GMThttp://hdl.handle.net/10829/82372017-06-01T00:00:00ZDesign of a Solar Househttp://hdl.handle.net/10829/7474
Design of a Solar House
Robinson, Michael
The Solar Decathlon has been created by the U.S. Department of Energy to test
the design, build, and operation of an energy efficient house. The newest addition to the
international solar decathlon competition has been moved to China. The competition will
take place August 2013 in Datong China. The goal of the houses being built is to create a
house that is both energy-efficient and architecturally pleasing to the public.
The house will be attached to the solar decathlon’s electric grid, septic, and water
systems. Since the house will be attached to the electric grid, electricity will always be
available for use. However, the whole purpose is to have a net electrical use of zero. To
have a net electrical use of zero, the house needs to be able to produce its own electricity
through solar panels, and consume the least amount of energy through the houses
appliances. During the competition week, the house will be put under mini contest that
will test the functionality of the house.
Building the house will need to be designed to be structurally sound on its own
foundation, so it will withhold the weight of the house and all of the housing systems
within. Not only does the house need to be strong but needs to be tight, so there is no
energy lose or energy gain between the outdoors and in. Getting the house to Datong
China has to be ready to be built upon arrival since only a week is given to build the
house on site. Therefore, the house will be partially built before shipping.
To overcome most of the major loads in the house, smart energy systems will be
used from the hot water system, to the lighting of the house. A monitoring, and control
system will be used to control the amount of energy being used at one time by the major
electrical load appliances. Also each appliance will be the most energy efficient to help
drive down the amount of energy needed for each appliance.
Advisory committee members: Jianxin Tang, Wallace Leigh. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Electrical Engineering at the Kazuo Inamori School of Engineering at Alfred University
Sat, 01 Sep 2012 00:00:00 GMThttp://hdl.handle.net/10829/74742012-09-01T00:00:00ZInvestigating the Structure, Solubility and Bioactivity of Na/Sr Bioactive Glasses/Glass-Ceramicshttp://hdl.handle.net/10829/7473
Investigating the Structure, Solubility and Bioactivity of Na/Sr Bioactive Glasses/Glass-Ceramics
Li, Yiming
This project was to investigate the structure, solubility and bioactivity of Na/Sr Bioactive
glasses. There are three sections to this study. The first section is the effect of Na+ and Sr2+ on the
structure and biocompatibility of the glasses. Three glasses (Ly-N, Ly-C, Ly-S) were formulated
with the substitution of sodium (Na+) and strontium (Sr2+) within the glass. X-ray diffraction
(XRD), X-ray Fluorescence (XRF), Differential Thermal Analysis (DTA), Hot Stage Microscope
(HSM) were used to characterize the series of glasses. Results of Network Connectivity (NC), Xray
Photoelectron Spectroscopy (XPS), Raman Spectroscopy, Magic Angle Spinning – Nuclear
Magnetic Resonance (MAS-NMR) presented that the three glasses have very similar structure and
Na+ and Sr2+ both act as network modifiers. Cell Culture testing was conducted to investigate the
biocompatibility and bioactivity of these glasses. The series of glasses have no negative influence
on the cell viability, and addition of Sr2+ increase the cell viability. The second section investigates
the mechanical durability of the bioactive glasses as a function of structure, solubility and
incubation time. Samples were sintered to amorphous and crystalline structures. Ion release
profiles were determined over 1, 7 and 30 days and in each case ion release was greatly reduced
when the materials were crystallized. pH changes were reduced with the onset of crystallization
compared to the amorphous counterparts. The highest concentrations of Na+ (216 μg/mL) and Si4+
(172 μg/mL) both coming from Ly-N with amorphous structure. Crystalline samples presented
much higher hardness values which did not reduce with respect to incubation time. However, the
hardness of amorphous samples was found to experience significant reduction. The third part is
simulated body fluid (SBF) testing and cytocompatibility of the glasses. In this section, sintered
glass powder discs (amorphous /crystalline) were used to do SBF trials. Each material was
subjected to maturation in SBF after 1, 7 and 30 days to describe any change in surface
morphology. Scanning Electron microscopy (SEM) was used to observe the calcium phosphate
(CaP) layers formed on the surface of each material. CaP deposition was observed predominantly
on Na+-containing amorphous and crystalline materials. Limited CaP deposition was observed on
the surface of Sr2+-containing crystalline materials. Cell culture analysis presented an increase in
cell viability with Na+-containing materials and a general reduction in cell viability with Sr2+-
containing material, however these reduction were not significant.
Advisory committee members: Nathan Mellott, Alexis Clare. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Biomaterials Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Mon, 01 Sep 2014 00:00:00 GMThttp://hdl.handle.net/10829/74732014-09-01T00:00:00ZFast Firing Porcelainhttp://hdl.handle.net/10829/7472
Fast Firing Porcelain
Colorado, Victor
Fast firing of commercial porcelains continues to be an important aspect of ceramic
manufacturing. The ability to predict the firing conditions necessary to densify a given
body could be quite valuable as a means to compensate for raw material chemistry
variations, the introduction of new production kilns, or the variation of an existing firing
cycle within a production environment. Previous work demonstrated that mineralogy,
microstructure evolution, and densification can be accurately predicted over a broad range
of temperatures and dwell times, but this work was only conducted on a single composition.
To allow the generation of a more widely applicable model, it is necessary to demonstrate
that this model is valid over a wide chemistry range. Ten compositions, fired over a broad
range of temperature and time conditions, were used to develop a model that is valid for
the experimental bodies in this thesis and is valid for the composition from previous work.
In addition, a more general relationship is proposed that relates densification to the amount
of glass formed during heat treatment.
Advisory committee members: Matthew Hall, Doreen Edwards. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Ceramic Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Mon, 01 Dec 2014 00:00:00 GMThttp://hdl.handle.net/10829/74722014-12-01T00:00:00Z